How to think in an endgame

The following is an excerpt from the great book 639 End Game Positions by Eric Schiller, discussing how to think in the endgame. Permission
to retransmit this part of the book was kindly granted by the publisher.

Once the game's major battles have died down, you have to adjust your thinking to the new circumstances presented in the endgame. Your goal is no longer
a checkmating attack against an enemy king, in most cases. First you must promote a pawn and gain a new queen. Circumstances may give you the luxury of
allowing your opponent to get one, too, but in that case you will need a material advantage or the initiative to gain a win.

The journey to the promotion square is a dangerous one. Each step up the board moves the pawn further and further from its home base, and it becomes
harder to defend. As it works its way through the enemy camp, the pawn must avoid capture, even if an enemy piece is the compensation. The easiest way
to draw a game where your opponent has a single remaining pawn often involves sacrificing a piece for the pawn. No pawn - no new queen.

Calculation is a bit different, too. Instead of aiming at a single target, the enemy king, you are trying to obtain one of the many positions that you
know to be a win against a best defense. Experience is important. The more endgames you play and analyze, the more likely you are to avoid letting a
win slip from your hands. Sometimes you just need to follow your intuition, moving pieces to squares where they will be more useful, hoping that your
personal must will remind you when the appropriate patterns become relavant.

In a few lucky cases, we can reduce the calculation to simple counting. More often, we need to rely on some "rules of thumb". There are some
geometry tasks we must execute perfectly, knowing, for example, when our king is in the square of the enemy pawn. If we have knights on the edge of the
board we need to watch for traps and make sure that their mobility is not restricted by enemy pieces. In rook endgames we need to remember which
operations are successful on the "long side" (4 files or ranks to edge) and which can be effective on the "short side" (3 files or ranks
to edge). When we have a bishop, we must keep in mind whether an enemy bishop is of the same color or opposite, and adjust strategy accordingly.